1. Myth: Humid Air Is Heavier Than Dry Air

There are more molecules of water in humid air which are lighter than molecules of air, he said.

"You can really feel the presence of humid air, but it is less dense," he said.

An airliner will need a larger runway length in dry air because there is more air resistance, and a baseball will go farther in humid air.

2. Myth: Tornadoes Don't Strike Cities or Mountainous Areas

The presence of rough terrain or skyscrapers tend to disrupt and weaken the circulation of tornadoes but that doesn't mean they avoid those areas, AccuWeather.com Senior Meteorologist Jack Boston said.

"You should take them just as seriously if a tornado warning is issued for your area," he said.

An F-5 tornado, known as the Moshannon tornado, plowed over hills and through the valleys of northern Centre County, Pennsylvania, on May 31, 1985, Wistar said.

Tornadoes have touched down in Texas and Midwestern cities and have hit skyscrapers, Wister added. New York City and other major cities of the East have also been struck by tornadoes.